Semiconductor Chip Metal Electrode Oxidation Adhesion
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Solution Overview
Problem
Existing semiconductor chip bonding methods fail to maintain strong adhesion in harsh environments, such as high-temperature and high-humidity conditions, leading to potential delamination during reflow soldering.
Innovation Solution
A semiconductor chip with a metal electrode featuring regions of different metals (e.g., copper and gold) with varying standard electrode potentials, where the more oxidizable metal forms an oxide layer for enhanced adhesion and the inert metal retains good electrical characteristics, and a via hole for electrical coupling, allowing for strong bonding with minimal electrical resistance increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single metal is used for the electrode, then electrical characteristics are maintained, but adhesion to adhesive is insufficient in harsh environments
Solution Approach 1:
The patent applies local quality by creating different metal regions at specific locations on the electrode. The first metal region (with lower standard electrode potential) is positioned at the bonding surface to provide oxidation and adhesion enhancement, while the second metal region (with higher standard electrode potential) is positioned at other areas to maintain low electrical resistance and prevent oxidation. This spatial differentiation of material properties resolves the contradiction between adhesion strength and electrical characteristics.
Solution Approach 2:
The patent uses composite materials by combining two different metals with distinct properties on the same electrode structure. The composite metal electrode consists of a first metal (e.g., copper) that oxidizes to improve adhesion and a second metal (e.g., gold) that remains inert to maintain electrical performance. This composite approach allows simultaneous achievement of strong adhesion and good electrical characteristics that neither metal could provide alone.
2Reliability
If adhesion is strengthened by increasing bonding area, then reliability improves, but device complexity increases
Solution Approach 1:
Instead of increasing the overall bonding area or adding complex surface structures, the patent applies local quality by modifying the chemical composition at specific electrode regions. The oxidation of the first metal at the bonding surface creates a chemically active layer that enhances adhesion without requiring increased surface area or complex geometries, thus avoiding device complexity increases.
Solution Approach 2:
The patent changes the chemical parameter (oxidation state) of the first metal region to enhance adhesion. By controlling the oxidation of the first metal (lower standard electrode potential) at the bonding surface, the patent creates a chemically modified interface that improves adhesion strength without altering the physical dimensions or geometric complexity of the electrode structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides robust adhesion and reliable electrical performance in harsh environments, preventing delamination and maintaining high peel resistance during reflow soldering.
Implementation Method 1
Of the first metal and the second metal, the one with the lower standard electrode potential is more likely to form an oxide layer on its surface. This oxide layer acts to improve adhesion to the adhesive.
Implementation Method 2
The metal electrode runs through the via hole to be electrically coupled to the element assembly
Data Source
AI summary
A semiconductor chip includes a single-crystal substrate and a metal electrode on the bottom surface of the substrate. The metal electrode has a region in which a first metal is exposed and a region in which a second metal is exposed, the second metal having a standard electrode potential different from that of the first metal.